This invention relates to chain drives. More specifically, this invention relates to a friction drive chain and a drive wheel therefor.
In the prior art, a wide variety of chains and chain drives are available. Typically, such chain drives comprise a chain formed from interconnected roller links having rollers carried on journal pins. The chain is receivable about a sprocket wheel between spaced peripheral teeth with the rollers being carried in the spaces between the teeth during operation. However, such chain drives require careful matching of the chain and sprocket wheel as well as relatively slow operating speeds to assure proper and accurate operation. Further, the use of sprocket wheels is not altogether desirable since high quality sprocket wheels are manufactured by expensive machining processes. Moreover, prior art chains typically comprise a plurality of moving parts which require periodic lubrication for continued operation.
Belt and pulley assemblies have been substituted for chain drives in some applications because of the elimination of chain rollers and expensive sprocket wheels, and because belt and pulley assemblies are relatively maintenance free. Further, belt and pulley assemblies are advantageous in that they can operate at running speeds considerably higher than chain drives. However, belt and pulley assemblies are greatly limited in load capacity and undesirably tend to slip at high load conditions or upon starting.
The friction drive of this invention overcomes the problems and disadvantages of the prior art by providing a chain drive wherein the sprocket wheel teeth and lubrication-dependent rollers are eliminated. Moreover, the friction drive of this invention provides the smooth-running, high-speed capabilities of belt and pulley assemblies without corresponding load or slipping problems.